But she’s arguably just as talented at communicating science and its significance in clear and compelling ways. I’ve gotten to know this through our chats on Warm Regards, the new climate science podcast we co-host with the meteorologist Eric Holthaus, who’s now writing for Pacific Standard.

But don’t take my word for it. Just listen to the latest episode, in which Jacquelyn explains the insights into past shifts in climate and ecosystems that have been gleaned by seeking and analyzing a host of indirect indicators — everything from pollen grains to the spores of certain fungi that lived on mammoth and mastodon dung. Eric appropriately calls paleoclimatology “CSI Pleistocene.”

Eric, whose own specialty is today’s (and tomorrow’s) weather, leads Jacquelyn through an explanation of her work on such “proxies” of past environmental conditions. Her favorite, Jacquelyn says, is a fungus that grew on the dung of big mammals. Its spores are incredibly durable and their comings and goings in layered lake mud reflect shifts in animal abundance over time. But then there’s the magic of plant pollen, as well.

Here’s a snippet of their conversation:

Jacquelyn | You can pull pollen out of the rocks just above the impact layer from the asteroid that killed the dinosaurs and the pollen grains look, for all intents and purposes, just like the pollen I work with.

Jacquelyn | I’m going to sound really nerdy for a moment. Pollen is made of the most resilient polymer known in nature – sporopollinen. You can dump all kinds of crazy chemicals on these pollen grains — really harsh like hydrofluoric acid, that will etch glass and dissolve sand, and the pollen grains are just fine.

Around the 13th minute in the recording, we shift to discussing how studies of past climate help build understanding of human-driven climate change and the built-in variability in the climate system that can occasionally produce extraordinarily potent droughts and floods.

I mention how two studies of lake mud, one centered in New England and the other Ghana, powerfully shaped my understanding of the need to consider past extremes in the context of today’s extreme weather events and what might be coming through this century and beyond with the greenhouse-gas buildup. Links to those studies are below.

Here’s are capstone thoughts from my partners:

Eric | the main idea here is we’ve always had climate change. We know about what has changed in the past from these really amazing records nature has laid down for us. The real lesson here is we need to pay attention to this as context for our own period of rapid change.
Jacquelyn | Whether you’re talking about corals or tree rings or globs of plants stuck together with pack-rat urine, there’s a remarkable amount we can tell about past climates from these proxy records that have done so much to contextualize our models and model predictability and climate records of the past, how the climate system works and how life responds.

The second thing I would say is, it doesn’t even matter if it’s the worst or the most, in terms of warming. Studying the past gives us some sense of what’s coming. But what it can’t tell us is how human societies will respond.

I hope you’ll download and listen, and share this podcast with anyone seeking some clarity on this complicated and consequential subject. I described the roots of our audio experiment, facilitated by the veteran podcast producer Stephen Lacey, in a recent Dot Earth piece.

Here’s more on the research mentioned above.

Photo

Mastodons graze on black ash trees in a Pleistocene swamp. Clues buried in lake beds are helping clarify what wiped out these and other big North American mammals.Credit Barry Roal Carlsen

The 2009 Science paper on lake-bed clues to transitions at the end of the ice age made The New York Times. Here’s a bit from Nicholas Wade’s article:

Ms. Gill found a clever proxy for these disappearances. A fungus known as Sporormiella has to pass through the digestive system to complete its life cycle, and its spores are found in animal dung. By measuring the number of spores in the lake deposits, the Wisconsin team documented the steady disappearance of large animals from 14,800 years to 13,700 years ago, they reported in Thursday’s issue of Science.

The next clue to emerge from the lake deposits was the pollen of new plants including broad-leaved trees like oak. This novel plant community seems to have emerged because it was released from being grazed by large mammals.

The third clue is a layer of fine charcoal grains, presumably from fires that followed the buildup of wood.
This sequence of events has direct bearing on the megafauna whodunit.

Here’s some of my coverage and commentary on lessons from the lake-bed studies showing past patterns of landscape-scouring superstorms in the Northeastern United States:

For at least 3,000 years, a drumbeat of potent droughts, far longer and more severe than any experienced recently, have seared a belt of sub-Saharan Africa that is now home to tens of millions of the world’s poorest people, climate researchers report in a new study.

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By 2050 or so, the human population is expected to pass nine billion. Those billions will be seeking food, water and other resources on a planet where humans are already shaping climate and the web of life. Dot Earth was created by Andrew Revkin in October 2007 -- in part with support from a John Simon Guggenheim Fellowship -- to explore ways to balance human needs and the planet's limits.